I ran the diagnostics on my 95 LS V6. I am getting code 15,17,24 as I understand these are just emissions issues and wont caus any perminant damage. I dont have the time or the money to replace them right away, I just wanted to make sure there would be no magor damage. The tutorial sais these will cause bad gas milage, I get 30 miles per gallon as is, I wonder what good gas milege is?